Thomas O’Brien has the eagle eye of a lifelong collector, but he will tell you that the best finds happen when you’re not really looking for them. And so, when the 1950s ranch next door to his 19th-century schoolhouse in Bellport, New York, became available, O’Brien could sense the workings of fate. The designer knew that the adjacent piece of land had once been part of the parcel on which the old school, his main residence (known by all in town as the Academy), now stands and that this was a rare opportunity to reunite long-separated sections of the vintage property. At first he focused on the landscape, protecting its beautiful old-growth trees and planting more gardens. But fortune favors the bold, and as he worked on the project, a bigger dream began to unfold.

A more historically authentic building within the gardens took shape in O’Brien’s mind. Following the footprint of the ranch house, he conceived an impeccably detailed conservatory-cum-residence that would serve as a practical repository for his myriad collections—decades of gathered art, antiquities, furniture, books, tableware, textiles, lighting, favorite antiques from Aero (his longtime shop in Manhattan), plus his own prototypes and out-of-production designs, all saved as a design resource. “Collecting is part of how I work,” he explains. “I’m always finding intriguing and wonderful things that I want to make into something for today. It’s just that for the longest time I didn’t have a place to put it all. A lot was in storage, like an entire history that was hidden away.”

Then O’Brien met his now-husband, fellow designer Dan Fink , by chance, at a benefit in New York City. And as the two traveled together—through Northern California, Europe, Japan—they began collecting more ideas and unique furnishings to make the evolving house into something new yet again: their true home together.

The result is a remarkable hybrid of residence, garden, and studio, affectionately called the Library. It’s a departure from the quietly modern, thoughtfully luxe interiors that have long been an O’Brien hallmark. And it just may be the closest the designer has ever come to fully realizing the creative vision he’s been nurturing for years.

At turns glamorous and intimate, the Library is a from-the-ground-up revival of the kind of historic, cultured, formal house and garden O’Brien has always admired—yet one that is elegantly curated for every dimension of fine living in the modern world.

“The house and its contents and the rhythms of how we live all inform each other,” Fink says appreciatively. “Thomas designed this space anticipating just the right spot or use for every single piece, even when no one else could see where it was all going to go. We both believe that beautiful things will always find a home, and this is a place where we’ve been fortunate to give that vision full expression.”